System of Particles and Rotational Motion · Question 4

Two identical bodies A and B of equal masses have initial velocities v1=4 i m/s and v2=4 j m/s respectively. The body A has acceleration a1=6 i+6 j m/s2 while the acceleration of the other body B is zero. The centre of mass of the two bodies moves in path.

1. circular
2. parabolic
3. straight line
4. elliptical

A wheel initially at rest is subjected to a uniform angular acceleration about its axis. In the first 2 s it rotates through an angle 1 and in the next 2 s it rotates through an angle 2. The ratio 2 1 is .

1. 6
2. 3
3. 4
4. 13

An object of uniform density rolls up the curved path with the initial velocity v0 as shown in the figure. If the maximum height attained by an object is 7v0210g (g = acceleration due to gravity), the object is a . [figure]

1. solid cylinder
2. ring
3. disc
4. solid sphere

A solid sphere of mass M and radius R is divided into two unequal parts. The smaller part having mass M/8 is converted into a sphere of radius r and the larger part is converted into a circular disc of thickness t and radius 2R. If I1 is moment of inertia of a sphere having radius r about an axis through its centre and I2 is the moment of inertia of a disc about its diameter, the ratio of their moment of inertia I2/I1= .

1. 35
2. 70
3. 140
4. 210

The position of an object having mass 0.1 kg as a function of time t is given as r= (10t2 i+5t3 j ) m. At t=1 s, which of the following statements are correct? Choose the correct answer from the options given below:

1. A, B and C only
2. B, C and D only
3. A, C and D only
4. A, B and D only

A particle is rotating in a circular path and at any instant its motion can be described as = 5t440- t33. The angular acceleration of the particle after 10 seconds is rad/s2.

1. 150
2. 120
3. 130
4. 170

Two blocks of masses 2 kg and 1 kg respectively, are tied to the ends of a string which passes over a light frictionless pulley as shown in the figure below. The masses are held at rest at the same horizontal level and then released. The distance traversed by the centre of mass in 2 s is m. (Take g=10 m/s2) [figure]

1. 3.33
2. 3.12
3. 2.22
4. 1.42

Moment of inertia about an axis AB for a rod of mass 40 kg and length 3 m is same as that of a solid sphere of mass of 10 kg and radius R about an axis parallel to AB axis with separation of 3 m as shown in figure below. The value of R is given as 2. The value of is . [figure]

Two circular discs of radius each 10 cm are joined at their centres by a rod of length 30 cm and mass 600 gm as shown in figure. If the mass of each disc is 600 gm and applied torque between two discs is 43 105 dyne.cm, the angular acceleration of the discs about the given axis AB is rad/s2. [figure]

1. 100
2. 22
3. 27
4. 11

A solid sphere of radius 10 cm is rotating about an axis which is at a distance 15 cm from its centre. The radius of gyration about this axis is n cm. The value of n is